这听起来像是你想实现一个UICollectionView，其中的单元格从左到右流动，当它们超过集合视图的宽度时会换行到下一行。这可以使用UICollectionViewFlowLayout来实现，这是UIKit提供的内置布局类。
若要创建从左到右排列单元格并换行到下一行的UICollectionViewFlowLayout，可以将滚动方向设置为水平，并根据需要调整minimumInteritemSpacing和minimumLineSpacing属性。在此处输入代码

class MyCollectionViewController: UICollectionViewController {
    // Set up the collection view flow layout
    let flowLayout = UICollectionViewFlowLayout()

    override func viewDidLoad() {
        super.viewDidLoad()

        // Configure the flow layout
        flowLayout.scrollDirection = .horizontal
        flowLayout.minimumInteritemSpacing = 10
        flowLayout.minimumLineSpacing = 10
        collectionView.collectionViewLayout = flowLayout

        // Register your custom UICollectionViewCell subclass
        collectionView.register(MyCustomCell.self, forCellWithReuseIdentifier: "MyCustomCell")
        }

        // Implement the UICollectionViewDataSource methods to provide the data for your cells
        override func numberOfSections(in collectionView: UICollectionView) -> Int {
            return 1
        }

        override func collectionView(_ collectionView: UICollectionView, numberOfItemsInSection section: Int) -> Int {
        // Return the number of items in your data source
        return myData.count
        }

        override func collectionView(_ collectionView: UICollectionView, cellForItemAt indexPath: IndexPath) -> UICollectionViewCell {
            let cell = collectionView.dequeueReusableCell(withReuseIdentifier: "MyCustomCell", for: indexPath) as! MyCustomCell

            // Configure the cell with data from your data source
            cell.configure(with: myData[indexPath.item])

            return cell
        }
    }

在自定义UICollectionViewCell子类中，可以设置autoresizingMask属性，以允许单元格在集合视图宽度更改时根据需要调整自身大小

class MyCustomCell: UICollectionViewCell {
    let label = UILabel()

override init(frame: CGRect) {
    super.init(frame: frame)

    // Set up the cell's subviews
    label.translatesAutoresizingMaskIntoConstraints = false
    contentView.addSubview(label)
    NSLayoutConstraint.activate([
        label.topAnchor.constraint(equalTo: contentView.topAnchor),
        label.leadingAnchor.constraint(equalTo: contentView.leadingAnchor),
        label.trailingAnchor.constraint(equalTo: contentView.trailingAnchor),
        label.bottomAnchor.constraint(equalTo: contentView.bottomAnchor)
    ])

    // Configure the label's appearance
    label.textAlignment = .center
    label.textColor = .white
    label.backgroundColor = .blue
}

required init?(coder aDecoder: NSCoder) {
    fatalError("init(coder:) has not been implemented")
}

func configure(with text: String) {
    label.text = text
}

override func layoutSubviews() {
    super.layoutSubviews()

    // Allow the cell to resize itself as needed when the collection view width changes
    contentView.autoresizingMask = [.flexibleWidth]
}
}

从你的代码来看，sizeForItemAt函数总是以一种方式创建单元格，你的集合视图总是有3个单元格在一行中。我建议你省略你的sizeForItemAt函数并创建一个简单的Xib单元格。在你的Xib中取一个标签，然后给予你的标签一个前导和尾随常量，然后将Xib注册到你的集合视图中。这将使您的每个单元格自动依赖于其标签，并从其标签推断其宽度。